1993 Other Jeep Models idle problem when warm?

i have a 93 jeep grand cherokee 5.2 v8.it idles fine when i start it when its cold,but when it gets warm the idle goes from normal being about .6 going to 1rpm then back down and up again.its a small noticable idle problem,what can i do t make it iidle normal at all times,i replaced the idle air control sensor,throttle postion sensor,did a complete tune up,and the idle problem still exists